In general, a plug-in hybrid electric vehicle (PHEV), which travels by using energy output from a battery as a power source, requires a charge of an internal battery according to driving of a motor of a vehicle, and in this case, a switching element called a contactor (or relay) is used in order to electrically conduct or block a current flowing between a charging source and the battery.
In the internal circuit of the PHEV, when it is necessary to protect various elements in a situation where an overcurrent exceeding a threshold value flows, an operation state of a contact point of the contactor is changed from an open state to a connection (close) state and a current in a circuit is blocked, thereby protecting various elements from the overcurrent.
In the meantime, the contactor may be generally implemented with contact points and a contactor coil, and when power is supplied to the contactor coil and electromagnetic force is generated, the contact points are in contact with one another and a current may be conducted, and in this case, the supply of power to the contactor coil is generally available through a contactor coil control unit.
The contactor coil control unit may allow electromagnetic force to be generated in the contactor coil by supplying power to the contactor coil, and in contrast to this, the contactor coil control unit may also collect the electromagnetic force of the contactor coil by blocking the supply of power.
In this case, when the contactor coil control unit applies an operation signal which unintentionally stops an operation of the contactor coil due to a sudden failure to the contactor coil, the operation of the contactor coil may be unintentionally stopped, and thus, there is a concern that the current conduction in the circuit is blocked while the contact points of the contactor are opened.
Particularly, when the conduction of the current in the circuit connected with the motor and the battery is blocked during the operation of the vehicle, a rotation of the motor is stopped and thus the vehicle suddenly stops, and when the corresponding vehicle is travelling at an overspeed, a safety accident may be incurred by the sudden stop.
In order to solve the various problems, contactor detecting technologies and methods of diagnosing an abnormal operation of a contactor and handling the abnormal operation have been developed in the related art, but when the contactor coil control unit applies an abnormal signal, the related arts cannot accurately determine whether the corresponding abnormal signal is a signal generated by an external impact of a vehicle or a signal generated by an actual failure of the contactor coil control unit, and particularly, the related arts have limitations in that there is no technology for maintaining a connection state of a contact point of a contactor for a predetermined time in a situation where an abnormal signal is applied from the contactor coil control unit, so that there is a concern that the contact point of the contactor is opened during an operation situation of a vehicle, or forcibly opening the contact point of the contactor in a situation where an operation of the vehicle is impossible.
Accordingly, in order to solve the various problems of the contactor, and the technology and the method for detecting, diagnosing, and controlling a contactor in the related art, the present inventor develops a system and a method of preventing a contactor from being abnormally opened through a real-time operation detection, in which when a contactor coil control unit, which applies an operation signal to a contactor coil (relay coil) that opens or connects contact points of a contactor (relay), during a travelling of a vehicle applies an abnormal signal to the contactor coil by an external reason or a failure, the abnormal signal is detected in real time, so that it is possible to prevent the contact point of the contactor from being unintentionally opened by the abnormal signal, and particularly, it is possible to prevent an operating vehicle from being suddenly stopped by determining whether the vehicle actually travels based on a maintenance time of the abnormal signal and whether the abnormal signal is applied due to an actual failure of the contactor coil control unit.